shift kit debate

heres the scoop. my 904 auto in my 72 duster has what appears to be either a leaky shift shaft seal or kick down shaft seal. either way it looks like I have to drop the pan and valve body to swap in new ones.

so I figure, if I am going to drop the trans pan and valve body I might aswell look into a shift kit to toss in while I am right there....some new fluid,filter and pan gasket and be done with it.

im not going to do this right away as im getting the car prepped for primer and paint right now. but I would like to get my ducks in a row and figure out what the plan is ahead of time.

I don't want to get all fancy with this ( full manual,reverse manual ...ect...ect...) and im working with a budget too. The main goal is a little firmer shifts.

I found a few of them on summits site ( not sure which one I would need or what the main differences in them are ....some appear to be the exact same kit....yet have different part numbers.'

anyhow. Ill post the links and if you guys could tell me which ones are worth a crud and why and any tips/advice...id appreciate it, thank you in advance.

http://www.summitracing.com/parts/TRG-TF-1/

http://www.summitracing.com/parts/BMM-10225/

http://www.summitracing.com/parts/BMM-10226/

http://www.summitracing.com/parts/BMM-10228/

http://www.summitracing.com/parts/TCI-122600/

http://www.summitracing.com/parts/TAC-17810/

http://www.summitracing.com/parts/TAC-17811/